Identification of Campylobacter jejuni, Campylobacter coli and Campylobacter lari by the nucleic acid amplification system NASBA®

NASBA(R), an isothermal amplification technique for nucleic acids, was evaluated for the specific identification of Campylobacter jejuni, Camp. coli and Camp. lari. A set of primers and a probe were chosen from the 16S rRNA sequence of Campylobacter. The probe was hybridized in solution with the amplified nucleic acids of 12 Campylobacter species and nine other Gram-negative bacteria. The probe was shown to hybridize specifically to the amplified single-stranded RNA of Camp. jejuni, Camp. coli and Camp. lari in an enzyme-linked gel assay (ELGA). In a Camp. jejuni model system the combination of NASBA(R) and ELGA was able to detect ca 1000 rRNA molecules. The presence of an excess of Gram-negative bacteria did not influence the sensitivity of detection. A number of 6 cfu of Camp. jejuni, present in a total count of 4 x 10(6) cfu of Gram-negative bacteria, resulted in a positive hybridization signal